1 files changed, 4 insertions, 2 deletions

diff --git a/lisp/mail/smtpmail.el b/lisp/mail/smtpmail.el
index 4d19e9371fd..66c4bdd8df7 100644
--- a/lisp/mail/smtpmail.el
+++ b/lisp/mail/smtpmail.el
@@ -691,8 +691,10 @@ This is relative to `smtpmail-queue-dir'.")
                           (>= (car response-code) 400))
                       (throw 'done nil)))
               (dolist (line (cdr (cdr response-code)))
-                (let ((name (mapcar (lambda (s) (intern (downcase s)))
-                                    (split-string (substring line 4) "[ ]"))))
+                (let ((name
+                       (with-case-table ascii-case-table
+                         (mapcar (lambda (s) (intern (downcase s)))
+                                 (split-string (substring line 4) "[ ]")))))
                   (and (eq (length name) 1)
                        (setq name (car name)))
                   (and name